11 



311 



Leucosides vittata (Stimpson). 



Leucosia vittala Alcock. LXV, 232, 1896; Stimpson, Smithson. Mise. Coll., XLIX, 149, pl. XVlll, fig. 3, 

 3 a, 1ÜÜ7. 



Sound at Koh Chang, 3—5 fath., soft clay; 1900; 2 juv. 

 Onychomorpha lamelligera Stimpson. 



Onycliomorpha lamelligera Alcock, LXV, 236, 1896; Stimpson, Smithson. Mise. Coll., XLIX, 164, pl.XIX, 

 figs. 8. 8a, 1907. 



North of Koh Kam, 10 fath., shell bottom; II. 6; 1 J". Koh Lan, 30 fath., 

 mud; III. 2; 1 ? ovig. 



The abdomen of the male has only three segments, the second to sixth in- 

 clusive being fused and bilobed in its widest part. 



Cryptocnemus mortenseni Rathbun. 



Crgptocnemus mortenseni Rathbun, Proc. Biol. Soc. Washington. XXII, 107, 1909. 



Nearly related to C. pentagonus Stimpson. Carapace equally broad, but with 

 the margin of the posterior half regularly arched, without poslero-lateral angles; 



Fig. 2. Cryptocnemus mortenseni, 

 type c?, 3-8 mm. wide. 



Fig. 3. Cryptocnemus mortenseni, 

 type c?, 3 8 mm. wide, ventral view. 



margin of anterior half slightly angled at the hepatic region; front ascending, its 

 edge arcuate, not acute as in C. pentagonus, forming a very shallow reentering 

 angle with the hepatic margin. Carapace smoothly rounded in the middle and 

 surrounded by a thin striated rim as in Onychomorpha lamelligera; rim widest in 

 the postero-lateral portion; from the hepatic angle its sharp edge is continued 

 downward to the anterior margin of the buccal cavity, and forms the lower edge 

 of a narrow facet, of which the upper margin, or true margin of the carapace, is 

 bluntly edged and in its outer portion not well defined. 



Merus of outer maxilliped as long as the ischium. 



Chelipeds about I'/i times as long as the carapace, nearly naked. Inner and 

 outer margins of arm and propodus and outer margin of wrist and dactylus with 



40" 



